Open the Photos app
Select the photo you want to edit
Tap Edit in the top-right corner
Use the adjustment tools to change light, color, and black point
Use the filter tools to apply a preset look
Use the crop and rotate tools to straighten, crop, or flip the photo
Tap Done to save the changes
Tap Edit again if you want to make more changes
Tap Revert to undo all edits and restore the original photo